The manipulation of the dispersion properties of a Bose-Einstein
condensate
(BEC) with moving optical lattices has enabled considerable
control of atomic
matter waves and, more recently, the generation of bright matter
wave solitons [1].
Here, we computationally propagate BEC's through periodic optical
potentials
of finite spatial/temporal lengths. It is seen that to vary the
effective
mass requires potentials that are relatively strong compared to the
transverse waveguide confinement. The role of both the linear and
non-linear wave mechanics in practical issues such as loading the
atoms
into the potentials are explored. We also report on work in progress
examining matter waves propagation through a chip-based magnetic
lattice [2].
$[1]$ Eiermann, B \textit{et.al} Phys.~Rev.~Lett. \textbf{92}
230401 (2004) \\
$[2]$ G{\"u}nther, A \textit{et.al} Phys.~Rev.~Lett. \textbf{95}
170405 (2005)